diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/README | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/src/backend/optimizer/README b/src/backend/optimizer/README index 99203968ba1..88cdbc32947 100644 --- a/src/backend/optimizer/README +++ b/src/backend/optimizer/README @@ -297,9 +297,6 @@ planner() handle UNION/INTERSECT/EXCEPT, GROUP BY, HAVING, aggregates, ORDER BY, DISTINCT, LIMIT --query_planner() - pull out constant quals, which can be used to gate execution of the - whole plan (if any are found, we make a top-level Result node - to do the gating) make list of base relations used in query split up the qual into restrictions (a=1) and joins (b=c) find qual clauses that enable merge and hash joins @@ -318,11 +315,11 @@ planner() Back at standard_join_search(), apply set_cheapest() to extract the cheapest path for each newly constructed joinrel. Loop back if this wasn't the top join level. - Back at query_planner: - put back any constant quals by adding a Result node Back at grouping_planner: + convert Path tree returned by query_planner into a Plan tree do grouping(GROUP) do aggregates + do window functions make unique(DISTINCT) make sort(ORDER BY) make limit(LIMIT/OFFSET) |